Prokaryotic expression of HN gene of bovine parainfluenza virus type 3 and the establishment of indirect ELISA method / 病毒学报

The prokaryotic expression plasmid pQE30-HN of hemagglutinin-neuraminidase (HN) protein gene of bovine parainfluenza virus type 3 (BPIV3) strain HJ-1 was expressed by IPTG induction in E. coli XL1Blue. The recombinant HN protein(rHN) was purified by electroeluting method, and used as coated antigen. An indirect enzyme-linked immunosorbent assay (ELISA) was developed to detect the antibody valence of BPIV3. The best working conditions of ELISA were as follows: the antigen concentration was 6 microg/mL; the serum dilution was 1:50; the blocking reagent was 5% skimmed milk; the blocking time was 60 min at 37 degrees C; the second antibody concentration was 1:10 000; The cut-off value was 0.30. The method revealed a good specificity, no cross-reaction to the positive sera of BCV, IBRV or BRSV was observed. We applied the method to detect 323 serum samples of dairy cow in Heilongjiang Province, the seropositivity rate of BPIV3 was about 58%. The indirect ELISA established provided a technological basis for the development of ELISA kit.

Identification and Phyletic Evolution Analysis of Actinomyces hyovaginalis from Swine / 微生物学通报

A strain was isolated from internal organ of died porcine about 8 weeks with purulent pneumonia,arthritis,pyogenic arthritis and endocarditis in April 2007.Objectives of the study are to confirm the genus of the strain,pathopoiesis,and drug sensitivity.The mainly study methods:the first,the strain was identified by the phenotype and the characteristics of the biochemistry,sequence 16S rDNA genes of the strain was analyzed by molecular biology technology,finally animal experiment and drug sensitivity testing were done.The results of the phenotype and the characteristics of the biochemistry showed that it is greatly similar to Actinomyces hyovaginalis,16S rRNA sequence analysis exhibited the homology achieved to 99.2% com-pared with group III strains of Actinomyces hyovaginalis,and the phyletic evolution analysis also indicated that it has mostly relationship with group III strains of Actinomyces hyovaginalis.Animal experiment dis-covered it has highly pathogenicity to Mus musculus albus;Drug sensitivity testing showed that it is hyper-sensitive to Erycin,Gentamicin and Amikacin.So,the result of the study confirmed that the strain is Actin-omyces hyovaginalis III with the pathogenicity.